1 // We avoid relying on anything else in the crate, apart from the `Debug` trait.
3 use std::cmp::Ordering;
4 use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
6 /// A blueprint for crash test dummy instances that monitor particular events.
7 /// Some instances may be configured to panic at some point.
8 /// Events are `clone`, `drop` or some anonymous `query`.
10 /// Crash test dummies are identified and ordered by an id, so they can be used
11 /// as keys in a BTreeMap.
13 pub struct CrashTestDummy {
21 /// Creates a crash test dummy design. The `id` determines order and equality of instances.
22 pub fn new(id: usize) -> CrashTestDummy {
25 cloned: AtomicUsize::new(0),
26 dropped: AtomicUsize::new(0),
27 queried: AtomicUsize::new(0),
31 /// Creates an instance of a crash test dummy that records what events it experiences
32 /// and optionally panics.
33 pub fn spawn(&self, panic: Panic) -> Instance<'_> {
34 Instance { origin: self, panic }
37 /// Returns how many times instances of the dummy have been cloned.
38 pub fn cloned(&self) -> usize {
39 self.cloned.load(SeqCst)
42 /// Returns how many times instances of the dummy have been dropped.
43 pub fn dropped(&self) -> usize {
44 self.dropped.load(SeqCst)
47 /// Returns how many times instances of the dummy have had their `query` member invoked.
48 pub fn queried(&self) -> usize {
49 self.queried.load(SeqCst)
54 pub struct Instance<'a> {
55 origin: &'a CrashTestDummy,
59 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
68 pub fn id(&self) -> usize {
72 /// Some anonymous query, the result of which is already given.
73 pub fn query<R>(&self, result: R) -> R {
74 self.origin.queried.fetch_add(1, SeqCst);
75 if self.panic == Panic::InQuery {
76 panic!("panic in `query`");
82 impl Clone for Instance<'_> {
83 fn clone(&self) -> Self {
84 self.origin.cloned.fetch_add(1, SeqCst);
85 if self.panic == Panic::InClone {
86 panic!("panic in `clone`");
88 Self { origin: self.origin, panic: Panic::Never }
92 impl Drop for Instance<'_> {
94 self.origin.dropped.fetch_add(1, SeqCst);
95 if self.panic == Panic::InDrop {
96 panic!("panic in `drop`");
101 impl PartialOrd for Instance<'_> {
102 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
103 self.id().partial_cmp(&other.id())
107 impl Ord for Instance<'_> {
108 fn cmp(&self, other: &Self) -> Ordering {
109 self.id().cmp(&other.id())
113 impl PartialEq for Instance<'_> {
114 fn eq(&self, other: &Self) -> bool {
115 self.id().eq(&other.id())
119 impl Eq for Instance<'_> {}